Intercommunication telephone system



July 12, 1932.

W. FEIND INTERCOMMUNI CATION TELEPHONE SYSTEM Filed Dec. 18, 1929 Patented July l2, 1932 {ST-AT PA EN OFFICE V w ALTER FEIND, on BERLIN-sIEMENssTAnm, GERMANY, Assrenon T0 sI'EMENsn HALSKE AxTIENGEsEn scHArr, os- BERLIN-.SIEMENSSTADTQGERMANYV i;

mrnnacomnum mlon rstnriic vn pr ic ti ed Dece b 1929 se ia n The usual 'intercommunication"telephone systems for local and main exchange ,traflic are P ided with a main at on for a s e -Q ing main exchange calls, this main station being provi ed with a m in-exch g b911, o

' that only at that station can a signal begiven to notifyan incomingcall from the main ex change. Therefore in such systems it is essential that someone must always be'ready at the main station to answer calls in order" that a satisfactory and reliable service can V be provided.

But it is oftenimp ossible for the attendant Preferably the arrangementis such that ,a relay connected to the main exchange line effects over a relay speciallyprovided for the purpose the successive connecting up of switching relays provided at all the stations. and also prepares thecircuit of the exchange bell. Atime relay associated with every t y?- tion effects the connecting up of the switch ing relay of the next extension station, which disconnects the switching relayandthus also 1 the bell of thepreceding station. Y i A a The invention will be better understood by referring to the following description which taken in conjunction with the accompanying drawing discloses a preferred method ofcarryingit into effect. j

incoming call over the. main exchange' 7 line a, b operates the relay A, which closes its contact- 1 in 'the'lead 0 thereby operating the slow acting relay which is connected in this lea'd c.

The stations S 1, S 2 an'dS 1.3 of these the station S 1 being assumed to be the main stationy are provided withswitching relays F, Gand N; Relay "F" of the main stationihas 1 contacts 355 and 6;:relay is provided with series with a condenser K.

' over winding HW 1' and contact- 19 to 415,940, and iniGermany Decemhe1 22, 192s.

contacts 7, 8, 9 and 10; while relay N of the last extension station'ha's the contacts 11,12, 13, 14 and '15. Contacts 7,11 and 14 are back contacts, one" additional contact being re-" quired forevery additional extension station.

Every station also has a timing device which cancomprise for example a thermostat with a winding suchjas HWl. Thethermostat ;at the main station S 1 is provided witha front contact 16, while at'the intermediate extension stations such as S 2 it is provided with a front contact17 except in the last extension station'S3, where it is provided with a back contact 18. A relay S controlled bya main exchange key serves to switch oh the batter co'nnectionto main exchange bells located at c the extension stations-andfor that is provided with a back contact '19.

If the bell at the main station is to ring as long as the call remainsunanswered, this bepurpose ing advisable where the attendantat the main station is liable to be absent for only ashort time, the main station is provided with an al-' ternating current bell-R connected directly across the main exchange line 'leads tab in In this case the bell 1 is omitted. Relays A and 'H pull up their contacts 1," 2 and '3 when an impulse of ringing current l-is received over the main exchange line, contact 3 closes'a circuit from over contact 3, windingv of relayrF, backcontacts 7 and 6' .14 to Relay F-thereupon operates and closes'its contacts 4, 5' and 6, thereby establishing a circuit from overcontact 2, contact '6, bell W 1 and contact19'of relay Sto At the same time contact 4;close's a locking circuit for relayF over contacts? and 14; while contact 5 closes a circuit from After a short intervalfduring which the bell is W 1 ringsithe' thermosta-twith winding H'l/V 1 closes its contact 16 thus causing relay G of .the extension' station SQflto be connected up in a'circuit' from )Lover contact 16;winding of 'relay-G,1backcontact 11 to i' Relay G now operates and opens contact 7 c Stir thus disconnectingthe right-hand terminal *ofrelay F. The latter therefore opens its,

contacts, thus interrupting the circuit of'the '1 themain exchange ringing signal is now'heard V at the second station. If the call is not: answered at this station within a short interval, the thermostat operates and by closing contact 17 causesthe bell W2 to be disconnected and the bell of the next extension station to be connected up in a manner similar to that already described.

the relay N is connected up in the same manner asat the preceding stations. Relay, N

opens contact 11, therebydisconnecting the relay of the preceding station; and closes its contact 12, thereby completing a locking circuit for itself. At contact 15 a circuit is completed for the bell Wn, and at contact 14 the circuit of relay F of the main station is opened, whereupon this relay fallsaway. Contact 13 is closed at the same time and completes the circuit of the thermostat winding HW n which operates after a short interval and at its back contact 18 disconnects the right-hand terminal of relay N. Relay N releases and again connects up relay F which operates. and again connects up the bell WV 1. This continuous transfer of the main exchange signal through all stations continues until at one of them the receiver is taken down and the main exchange key is operated, whereupon relay S energizes and at contact 19 opens the circuit of the bells so that theycannot ring any more. The answer'- ing subscriber then sets the main exchange caller in communication with the wanted subscriber.

' in place thereof the bell R canfbe fitted in the main exchange line, where it rings so long as calling takes place. But the relays at the difierent'stations operate'in the same manner asthat described above. I, lVhat is claimedis 1. In a telephone system, a local exchange; a main-station and a plurality of extension stations in said local exchange, a main ex-- change having a trunk line extending to the main station tor'calling the same, a call signal at sa d mam statlon and eachof saidextension stations, means respons ve to a call from said main exchangefor operating the call signal at said main station, means at said mam and extension-stations for automatic'ally operating the call signals at each of saidstationsin succession until theca-ll "from said main exchange is answered, and

means for repeating the successive operation calling said local exchange, a call signal at each of said stations, a switching relay at each-of said stations for operating the associated call' signal, means controlled by said switchmg relays for operating the switching relays of the next stations in succession to operate their associated call signals one after :another, and a slow operating relay at said main station responsive to a calljrom the a a main exchange forinitiatingthe operation When the call reaches the last station 83' exchange for operating said switching relays in succession to operate their associated call signals.

4;. In a telephone system, a main exchange and a local exchange, a main station and a plurality of; extension stations atsaid local exchange, means. in said main exchange for calling sa d local exchange, a call signal at said main station and at each of said extension stations, a switching relay at each of said stations for operating its associated call signal, a timing device at each of said sta} tions controlled by the associated switching relay, andmeans controlled by said timing device's responsive to a call from said main exchange for operat ng the SWlllClllIlglGlfi/YS V h h 5 of the next succeeding stations in succession As previously mentioned, the bell W 1. a can be omitted from the main station S 1 and i plurality of extension stationsatsaidlocal exchange, means in said main exchange for calling said local exchange, a call s gnal at said main and each of said extension stations,

a switching relay at said main and each of.

said extension stationsfor operating the assoii ciated call signal, means responsive to a call from said main exchange forlfloperating the switching relay at said main station, means responsive thereto for operatingthe switch ing relays of said extension stations in succession, andmeans responsive to the'opera-v tion of said relays for releasing the preceding switching relay 6, In a telephone system, a main exchange and a local exchange, a main station ,and a. plurality of extension stations atsaid local 1 exchange, meansin said main exchangefor calling said local exchange, a call sign l 13o said main and each of said extension stations, a switching relay at each of saidjstations for operating its associated call signal responsive to a call, a timing device at each of said stations operated by the associated switching relay to close the circuit of the switching relay of thenext successive station to operate the call signal thereat, and an answering relay responsive when the call is answered for releasing said timing devices and said call signals. r

7. In a telephone system, a main exchange, a local-exchange connected to said main exchange, a main station and a plurality of extension stations at said local exchange, call signals at each of said stations, means at said main station responsive to a call from the main exchange for operating the call signal thereat, means for automatically operating the call signals at said extension stations in. succession, and means for repeating the suc-' cessive operation of the call signals until the call is answered. r V

V 8. In a call signalling system, a main sta- 95 tion and a plurality of extensionstations, call signals at each of said stations, means for operatingthe call signal at said main station, means for operating the call signals at said "extension stations in succession, and means for repeatedly operatingthe' call signals in succession. p I, t

'9. In a call signalling system, a main station and a plurality of extension stations, call signals at each of said stations, means for answering said call signals, means for operating said call signals at each of said stations in succession, means for repeating the successive operation of said call signals and means responsive to the answering of the call 40 signal at said stations for disconnecting said call signals.

10. In a call signalling system, a main sta tion and a plurality of connecting extension stations, call signals at each of said stations,

4 means for operating the call signal at said main station and all of saidextension stavtions in succession, and means at each of said stations for automatically disconnectingthe call signal of the preceding station and op- 5 erating the call signal of the next succeeding station. 1 V V In testimony whereof I affix my-signature;

V WALTER FEIND. 

